Recoil device for machine guns



Aug Z7, 1940. R. H; s. HUGHES 2,2l287 RECOIL DEVICE FOR MACHINE GUNSFiled June 18, 1957 3 Sheets-Sheet 1 a- N D a E au @s m u n. l \`\J 5 ia l ug- 27, 1940. R. H. s. HUGHESv 2,212,687

RECOIL DEVICE FOR MACHINE GUNS Filed June 18. 1937 3 Sheets-SheetI 2 47e m J f4@ Q y m ff i l l Amig. 2?, 1940. R.' H. s. HUGHES' 2,2287

REcoIL'DEvIGE FOR MAGHINE GUNS Filed June 18. 1937 s sheets-sheet 3Patented Aug. 27, 1940 Robert H. s. Hughes, Baltimore, Ma., assigner ofone-half to Milton Roberts, Baltimore, Md.

Application June 18, 1937, Serial No. 149,020

4 Claims.

This invention relates to machine guns of the type having reciprocablebarrels, and particularly to means for controlling the recoil of thebarrel and the rate of firing of the gun. By means of my invention, therate of firing of the gun may be varied while the gun is in action.

In carrying out the invention, I provide in front of the muzzle of thegun barrel a recoil controlling attachment which is supportedindependently of the barrel and preferably upon the jacket whichsurrounds the barrel and is connected to the gun casing. This attachmentcomprises a hollow body having a seal port in line with the bore of thebarrel and also having forwardly and rearwardly directed ports out ofline with the bore of the barrel, and also laterally directed bailleports, for the discharge of the products of combustion. Valve mechanismis provided for closing all of the ports, or for opening the forwardlydirected ports only, or for opening the rearwardly directed and bailleports only. By these means, as hereinafter explained, the recoil forceapplied to the barrel may be increased or decreased, as desired. I alsoprovide in the gun casing means for adjusting the tension of the springwhich returns the barrel and breech bolt to their firing positions, andI provide means under the control of the operator for simultaneouslyadjusting the valve mechanism on the recoil device and the springtensioning means so that the rate of ring may be varied while the gun isin action.

In the accompanying drawings:

Fig. 1 is a side elevation of a machine gun equipped with myimprovements;

Fig. 2 is a rear end view of the same, parts being broken away;

Fig. 3 is a vertical longitudinal section through a portion of thecasing showing the mechanism for adjusting the tension of the spring foroperating the bolt and for simultaneously actuating the flexible shaftwhich operates the portcontrolling means;

Fig. 4 is a section on the line 4 5 of Fig. 3;

Fig. 5 is a section on the line 5-5 of Fig. 3;

Fig. 6 is a section on the line E-S of Fig. 2;

Fig. 'I is a central longitudinal section through the forward ends ofthe gun barrel and jacket and through the recoil controlling device;

Fig. 8 is an end view of the controlling device, looking from right toleft in Fig. 7;

Fig. 9 is a section on the line 9-9 of Fig. '7; and

Fig. 10 is a section taken diametrically through the valve whichcontrols the baille ports and discharge ports.

Referring to the drawings:

I indicates a machine gun as a whole, 2 indicates the breech casing, 3indicates the barrel jacket and 4 indicates the movable gun barrel,

the bore of which is indicated at 5. A front mounting bracket 4' and arear mounting bracket 5 are secured to the breech casing, these bracketsbeing adapted for connecting the gun to a suitable support. Rear andforward sights, 6 and 1, respectively, are shown mounted on the jacket.

The breech casing 2 is provided with the usual projectile feedingmechanism indicated at 3. Operating handles 9 are attached to the rearend of the casing 2, by means of supports l0, and a trigger mechanism Ilis arranged close to the handles. l

My recoil device R is secured to the barrel jacket 3 and the forward endof the gun barrel is movable longitudinally within the rear portion ofsaid device. The bolt i5 of the machine gun is conventionally shown inFigs. 3 and 5. The bolt has a socket I6 to receive the forward end of arod il and the forward portion of a spring I8 which is coiled about therod. The rear end of the rod ts within a socket I9 in a block 20. Thisblock extends laterally through elongated slots 22 and 23 in the side ofthe breech casing and of a housing 2l which is attached to said casingand bears against an adjustable wedgeshaped stop 29, the slots forming aguideway for the block.

As in machine guns generally, the bolt l5 is adapted to be movedrearwardly after iiring by the recoil of the barrel and the force ofthis rearward movement of the barrel is used to cause ejection of theempty cartridge, to extract a cartridge from the cartridge belt anddeposit it into the breech, and, lastly it cocks the gun. The spring I 8is compressed by the rearward movement of the bolt and as the springexpands and moves the bolt forward the bolt loads the cartridge, locksthe breech and fires the gun,

In the present invention the tension of the spring is adjustable bymoving the stop 29 vertically. A vertically arranged shaft 24 extendsthrough openings 25 and 26 in the housing 2l and a collar 21, pinned tothe upper end of the shaft, supports its. The portion of the shaftwithin the housing is threaded as indicated at 28 and this threadedportion extends through a threaded opening 30 in the stop. The block 20has a beveled face 3| which engages the oppositely beveled face of thewedge-shaped stop 29. It will be-evident that if the threaded shaft isturned to adjust the stop 29 upwardly the block 20 will be moved toincrease the pressure on the spring I8, and if the threaded shaft isturned to adjust the stop 29 downwardly, the pressure of the block 20against the spring will be decreased.

A gear casing 32 is secured to the lower side of the breech casing, asshown in Figs. 3 and 4. The lower portion of the shaft 24 extendsthrough an opening 32 in the upper wall of the casing and on the lowerend of the shaft is secured a bevel pinion 33 which meshes with a bevelgear 34 rotatably mounted on a stationary shaft 35 which is supported inthe side Walls of the housing 32. A pinion 36 which is secured to androtates with gear 34 meshes with a large gear 31 secured to a shaft 38which extends through and is journaled in the side walls of the caslng3.2.

As shown in Fig. 6, the lever arm 39 is pinned to the end of the shaft38 at the rear of the casing 32. 'I'he lever arm is slotted as at 40 andlatch member 4l extends therethrough and is pivoted as at 42. As shownin Figs. 2 and 4, a toothed segment 44 is suitably secured to the casing32. The latch 4l is provided with a tooth 45 which is adapted to engagethe segment 44. One end of a helical spring 46 is fitted within a socket41 in the arm 39, and the other end of the spring bears against thelatch #il to normally hold its tooth in engagement with the toothedsegment d. A pointer 50 on the arm 38 indicates on an arcuate scale i9the setting of the arm.

From the foregoing it will be evident that by moving the arm 3S motionis transmitted through the gear train 31, 36, 9@ and 33, to the shaft2li upon which is threaded the wedge 29. of the shaft 2li will move thewedge vertically to increase or decrease the pressure on the driv ingspring i8. By the same movements of the arm 39 a cable i239, attached toone end of the shaft 38, will be rotated. This cable, which is encasedin a exible non-rotative covering H0, operates the port controilingvalves of my re coll device R so that any adjustment of the valves isaccompanied by an adjustment of the spring tensioning device. Theforward end of the cable is connected to a shaft it journaled in lugs 91and 98 depending from the body of the recoil device, and this shaftcarriesv gears lil and 804 for operating the valves. The recoil deviceR, as shown in Figs. 7 to 10, comprises a hollow body 68 having a sleeve5| which extends within the forward end of. the jacket 3 and is securedto the jacket by a collar 63 which is threaded onto the sleeve as shownat 62 and also has a threaded connection 64 with the inner wall of thejacket. A set screw 65 engaging the jacket, collar and sleeve, preventsrelative rotation of these parts. The recoil device is thus secured toand supported by the jacket which connects it to the breech casing.'I'he forward end of the gun barrel is externally threaded, as indicatedat 68, andan internally threaded collar 61 is threaded onto the barreland secured against rotation thereon by a set screw 69. This collar hasa smooth periphery and forms a bearing for the gun barrel within thesleeve of the recoil device. The forward end of the collar 61 issubstantially flush with the forward end of the gun barrel and formswith the end of the barrel a shoulder 18 of substantial area againstwhich the gas pressure is applied in the operation of the gun.

The body 60 has a cylindrical combustion chamber 10 therein, the rearpart of the ch'amber being formed by the part 6In of the sleeve 6l whichextends forwardly from the gun barrel, this portion of the chamber wallhaving a series of bailie ports 19 extending therethrough, and aninwardly extending annular shoulder lilb is formed at the forward end ofSaid portion, and from this shoulder the inner side wall of the Rotationchamber extends forwardly uto the periphery of an annular shoulder 14 atthe forward end of the chamber. The body has a tubular extension 1| atits forward end through which extends a seal port 12 which is in axialalinement with the bore of the barrel. From the forward part of thechamber discharge ports 13 extend rearwardly and outwardly through itswall, the outer ends of the discharge ports being forward-of the baffleports, so that when the ports are open and the gun is red the dischargefrom the rearwardly directed ports will be intercepted by the dischargefrom the baille ports, the arrangement of ports in this respect beingsimilar to the arrangement of ports in my Patent No. 2,191,484, datedFebruary 27, 1940.

In addition to the rearwardly directed ports and baille ports I alsoprovide intermediate the rearwardly directed ports, a circular series offorwardly directed ports 11, these commencing as grooves 11n in the sideWall of the chamber at the shoulder 10 and extending through the forwardwall of the chamber adjacent the tubular extension 1l, these forwardlyextending ports be ing in line with the shoulder 18 on the gun barrel.

An annular valve 88 surrounds the bodyportion and is movable to open andclose the rearwardly directed discharge ports and the baille ports. Asshown in Fig. 10, the valve has spaced openings 82 and correspondinglyspaced openings 83 adapted to register with the baille ports 19 andrearwardly directed ports 13, respectively, in one position of thevalve, to open said ports, and in another position of the valve all ofAthe ports will be closed.

On the forward end of thebcdy is arranged a disk-like valve 81, withcircularly spaced openings 86 adapted to register with the' forwardlydirected ports 11 in one position of the valve and to close said portsin another position of the valve.

The gear H00 on the shaft l has a tooth |82 adapted to engage a notch 94in the edge of the valve 81 which controls the forwardly directed ports,and the periphery |03 of this gear is adapted to engage arcuate surfaces95-96 at opposite sides of the notch to hold the valve in any positionof adjustment. Similarly the gear |04 on Shaft IDI has a tooth |01adapted to engage a notch 9| at the periphery of the valve and theperiphery |08 of this gear is adapted to engage arcuate surfaces 92 and93 at opposite sides of the notch 9| to hold the valve in any positionof adjustment. Cooling fins 84 are provided on the valve 80- and suchfins 88 are also provided on the valve 81, and ns I2 (Fig. '7) may beprovided on the body of the recoil controlling device, to dissipate theheat from these ports when the gun is in action, so that the valves willt closely and not be distorted by excessive heating of the ports.

In the positions shown in Figs. 7, 8 and 9 all valve controlled portsare closed, the control lever 39 is in the mid position as shown inFigs. 2 and 4 and the wedge 29 for adjusting the pressure on the springI8 is also in mid position. In this position of the lever 39 the highestgas pressure prevails in the combustion chamber of the recoil devicewhen the gun is fired, and hence the greatest gas pressure is applied tothe shoulder 18 on the gun barrel and there is practically no recoilpressure applied to the barrel jacket, on which the recoil controllingdevice is mounted. InI this mid position of the control lever thegreatest rate of re results because the gun bar- 4amasar rel is drivenbackwardly at high velocity and the pressure of the spring I8 is such asto ensure rapid return of the breach block and barrel.

Moving the control lever to the left in Fig. 2 (to the right as viewedin Fig. 4) adjusts the wedge 39 upwardly and increases the pressure onthe spring I8 and turns the shaft 38, cable I 09 and shaft IOIcounter-clockwise as viewed in Fig. 8. With a suiicient movement thetooth |02 on the gear |00, engaging the notch 94 in the valve 81, willcompletely uncover the forwardly directed ports, while the rear valve 80will remain closed; or by a shorter movement of the lever the forwardports can be only partly opened, leaving the rear valve closed. Openingthe forward ports lessens the gas pressure in the combustion chamberwhen the gun is fired, and hence the gun barrel will not be drivenbackward with the same velocity as when these ports are closed andalthough the wedge 39 will be adjusted upwardly in opening the forwardports, increasing the tension of the spring I8, the stored energy in thespring will not compensate for the slowing down of the rearward movementof the barrel, and the rate of fire will be decreased. The amount ofdecrease will depend upon the extent to which the forwardly directedports are open.

Moving the control lever to the right in Fig. 2 (to the left as viewedin Fig. 4) adjusts the wedge 39 downwardly and decreases the pressure onthe spring I8 and turns the shaft 38, cable |09 and shaft IOI clockwise,as viewed from the forward end of the control device, Fig. 8, orcounterclockwise as viewed in the section, Fig. 9. In this movement thetooth I02 on the gear |00 moves out of engagement with the valve 81,leaving the forwardly directed ports closed and the tooth |01 on thegear |08 moves the valve 80 to open the rearwardly directed ports I3 andthe baille ports 19. If the movement of the control lever is sufficientto completely open the rearwardly directed ports and the baille ports,the gas pressure in the combustion chamber when the gun is red will beat a minimum and the pressure applied to the spring I8 by the wedge 29will be at a minimum and the rate of re will be slowed down both by thereduced rearward velocity of the gun barrel and decreased energy storedin the spring which returns the barrel. In intermediate positions of thecontrol lever the rearwardly directed ports and baille ports may be onlypartly opened and the gas pressure, acting against the gun barrel whenthe gun is red, will be greater or less according to the position of thevalve 80 so that the velocity with which the barrel is driven backwardlywill be varied accordingly, thus varying the rate of re.

One important advantage of being able to change the rate of re while thegun is in action, is that the gunner may change the rate so as toeliminate what is commonly called resonance. While at one speed theremay be vibration, annoying the gunner, a slight adjustment of the rateof fire may substantially reduce this cause of annoyance.

I claim:

1. The combination with a machine gun comprising a reciprocable barrel,a breech bolt and a spring adapted to be placed under tension by therecoil of the barrel and to return the bolt and barrel to firingpositions, of a hollow recoil attachment supported independently of thebarrel at its muzzle, said attachment having in its wall a seal port inline with the bore of the barrel and having also forwardly directedports and rearwardly directed ports, out of line with the bore ofthebarrel, for the discharge of the products of combustion to theatmosphere to affect the force of the recoil, port controlling meansadjustable on the attachment for varying the effective areas of saidforwardly and rearwardly directed ports, means for adjusting the tensionof said spring, and manually controlled means for simultaneously movingsaid port controlling means and said spring tension adjusting means.

2. The combination with a machine gun comprising a reciprocable barrel,a breech bolt, a spring adapted to be placed under tension by the recoilof the barrel and to return the bolt and barrel to firing positions andmeans for adjusting the tension of said spring, of a hollow recoilattachment supported independently of the barrel at its muzzle, saidattachment having in its wall a seal port in line with the bore of thebarrel and having also forwardly directed ports and rearwardly directedports, out of line with the bore of the barrel, for the discharge of theproducts of combustion to the atmosphere to affect the force of therecoil, a valve adapted to open and close the forwardly directed ports,a valve adapted to open and close the rearwardly directed ports,manually controlled means for moving said valves in succession to eithertheir open or closed positions, as desired, and for simultaneouslyadjusting said spring tensioning means.

3. The combination with a machine gun comprising a reciprocable barrel,a breech bolt, a spring adapted to be placed under tension by the recoilof the barrel and to return the bolt and barrel to firing positions andmeans for adjusting the tension of said spring, of a hollow recoilattachment supported independently of the barrel and its muzzle, saidattachment having in its wall a seal port in line with the bore of thebarrel and having also forwardly directed ports and rearwardly directedports, out of line with the bore of the barrel, and balile ports at therear of rearwardly directed ports, a valve adapted to open and close theforwardly directed ports, a valve adapted to open and close therearwardly directed ports and baffle ports, manually controlled meansfor moving said valves in succession to either their open or closedpositions, as desired, and for simultaneously adjusting said springtensioning means.

4. 'Ihe combination with a machine gun comprising a casing and a barreljacket extending forwardly from the casing, of a hollow recoilcontrolling attachment having a sleeve fitting within and secured to theforward end portion of the jacket, a reciprocable barrelwithinthejacket.

said barrel having an external collar at its fortheir peripheries, andmanually controlled means for operating said valves from the rear end ofthe gun.

ROBERT H. S. HUGHES.

